SkyTEM–a New High-resolution Helicopter Transient Electromagnetic System

摘要: SkyTEM is a time-domain, helicopter electromagnetic system designed for hydrogeophysical and environmental investigation. Developed as rapid alternative to ground-based, transient measurements, the resolution capabilities are comparable that of conventional 40 × m 2 system. Independent helicopter, entire carried an external sling load. In present system, transmitter, mounted on lightweight wooden lattice frame, four-turn 12.5 square loop, divided into segments transmitting low moment with one turn high all four turns. The uses about 30 A turn-off time 4 µs; draws approximately 50 A, has 80 µs. shielded, overdamped, multi-turn receiver loop rigidly side transmitter loop. This essentially central-loop configuration 1.5 vertical offset. hover mode responses were within 2% those from ground-based Instrument bias level not concern high-altitude tests showed background noise higher than instrument level. By inverting sounding test site standard model then applying parameters compute forward response, measurements 5% flight heights 7.25, 10, 20 m. Standard field operations include establishment repeat base station in survey area where data acquired every hours, when refuelled, monitor stability. Data production successful detecting delineating buried-valley structure important investigations.